Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The development of protocols for the ex vivo generation of dendritic cells (DCs) has led to intensive research of their potential use in immunotherapy. Accumulating results show the efficacy of this treatment on melanomas which are highly immunogenic. However, its efficacy remains unclear in other tumors. In this study, allogeneic gastric cancer cell-DC hybrids were used to determine the efficacy of this type of immunotherapy in gastric cancer. Fusion cells of DC and allogeneic gastric cancer cells were generated by polyethylene glycol (PEG) and electrofusion. These hybrids were used to induce tumor associated antigen (TAA) specific cytotoxic T lymphocytes (CTLs). The DCs were successfully fused with the allogeneic gastric cancer cells resulting in hybrid cells. These hybrid cells were functional as antigen-presenting cell because they induced allogeneic CD4(+) T cells proliferation. CD8(+) T cells stimulated by the MKN-45-DC hybrid cells were able to kill MKN-45 when used for immunization. The CTLs killed another gastric cancer cell line, MKN-1, as well as a melanoma cell line, 888mel, suggesting the recognition of a shared tumor antigen. MKN-45 specific CTLs can recognize carcinoembryonic antigen (CEA), indicating that the killing is due to tumor antigens as well as alloantigens. This approach suggests the possible use of allogeneic gastric cancer cell-DC hybrids in DC based immunotherapy for gastric cancer treatment.
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PMID:Allogeneic gastric cancer cell-dendritic cell hybrids induce tumor antigen (carcinoembryonic antigen) specific CD8(+) T cells. 1589 83

MG7-Ag is a human gastric-carcinoma-associated antigen with a high specificity. So far it is remained unclear whether MG7-Ag is correlated with the in vivo cellular immune response of patients with gastric cancer. In this study, we detected the expression of the T cell receptor (TCR) repertoire of T cell subpopulations and cytokines in tumor-infiltrating lymphocytes (TIL), peripheral blood lymphocytes (PBL), and residue benign mucosal lymphocytes (NML) of patients with gastric cancer using semiquantitative RT-PCR. Our data showed that the expanded clones in CD8(+) NML and TIL and CD4+ NML and PBL in MG7-Ag-positive patients were significantly fewer than those of MG7-Ag-negative patients (p = 0.0360; p = 0.0026; p = 0.0065 p = 0.0109, respectively). The levels of IL-8 in CD8(+) TIL and TNF in CD4(+) TIL from the MG7-Ag-positive group were significantly higher than those from the MG7-Ag-negative group (p = 0.0302; p = 0.0177, respectively). Taken together, the results demonstrated a weaker T cell immune response and more proinflammatory cytokine secretion in MG7-Ag-positive patients with gastric cancer than in MG7-Ag-negative ones. This likely contributes to the poor prognosis in MG7-Ag-positive gastric-cancer patients.
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PMID:Expression of MG7-Ag in patients with gastric cancer correlates with weaker T cell immune response and more proinflammatory cytokine secretion. 1660 93

Toll-like receptors (TLRs) are important molecules that stimulate the innate immunity in order to eradicate microbial pathogens, after which the adaptive immunity emerges. The involvement of TLRs in the action mechanism of OK-432, a bacterial preparation, was investigated in the locoregional treatment of malignant ascites from gastric cancer. The expression of TLRs in ascites cells was analyzed using reverse-transcription polymerase chain reaction specific for TLRs and by flow cytometry using anti-TLR2, -TLR4, -CD4, -CD8, and -CD11c antibodies. These measurements were compared with the locoregional response of OK-432 immunotherapy for malignant ascites, as well as TNF-alpha producing potential, which was measured by ELISA, of ascites cells stimulated in vitro with OK-432. It was observed that OK-432 immunotherapy for malignant ascites showed 8 positive (67%) and 4 negative responses with the tolerable adverse effects of fever elevation and abdominal pain. The TNF-alpha production of ascites cells by in vitro OK-432 stimulation was significantly higher in responder patients than in non-responders. The clinical responses were correlated with the expression of the TLR4 gene of ascites cells. The TNF-alpha-producing potential of ascites cells by in vitro OK-432 stimulation was dependent on the existence of a CD11c + TLR-4+ cell population in ascites cells. OK-432 was highly stimulatory for TNF-alpha production of ascites cells compared with other biological response modifiers of PSK and LEM. These results suggest that TLR-4 expression on ascites cells of a macrophage lineage is essential for ascites cells to produce TNF-alpha in relation to OK-432 stimulation and for subsequent positive clinical responses in locoregional immunotherapy using OK-432 for malignant ascites from gastric cancer.
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PMID:Essential requirement of toll-like receptor 4 expression on CD11c+ cells for locoregional immunotherapy of malignant ascites using a streptococcal preparation OK-432. 1709 88

The chemotactic cytokines called chemokines are a superfamily of small secreted cytokines that were initially characterized through their ability to prompt the migration of leukocytes. Attention has been focused on the chemokine receptors expressed on cancer cells because cancer cell migration and metastasis show similarities to leukocyte trafficking. CXC chemokine receptor 4 (CXCR4) was first investigated as a chemokine receptor that is associated with lung metastasis of breast cancers. Recently, CXCR4 was reported to be a key molecule in the formation of peritoneal carcinomatosis in gastric cancer. In the present review, we highlight current knowledge about the role of CXCR4 in cancer metastases. In contrast to chemokine receptors expressed on cancer cells, little is known about the roles of cancer cell-derived chemokines. Cancer tissue consists of both cancer cells and various stromal cells, and leukocytes that infiltrate into cancer are of particular importance in cancer progression. Although colorectal cancer invasion is regulated by the chemokine CCL9-induced infiltration of immature myeloid cells into cancer, high-level expression of cancer cell-derived chemokine CXCL16 increases infiltrating CD8(+) and CD4(+) T cells into cancer tissues, and correlates with a good prognosis. We discuss the conflicting biological effects of cancer cell-derived chemokines on cancer progression, using CCL9 and CXCL16 as examples.
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PMID:Chemokine receptors in cancer metastasis and cancer cell-derived chemokines in host immune response. 1789 51

It has been reported that an increased population of regulatory T cells (Tregs) is one of the reasons for impaired anti-tumor immunity. Recently, Foxp3 has been reported as a reliable marker of Tregs. The authors investigated the frequency of Foxp3(+) Tregs within CD4(+) cells in TILs, regional lymph nodes and PBLs of gastric cancer patients (n = 45). Furthermore, to elucidate the mechanisms behind Treg accumulation within tumors, they evaluated the relationship between CCL17 or CCL22 expression and the frequency of Foxp3(+) Tregs in gastric cancer. CD4(+)CD25(+)Foxp3(+) Tregs as a percentage of CD4(+) cells were counted by flow cytometry and evaluated by immunohistochemistry. Moreover, an in vitro migration assay using Tregs derived from gastric cancers was performed in the presence of CCL17 or CCL22. As a result, the frequency of Foxp3(+) Tregs in TILs was significantly higher than that in normal gastric mucosa (12.4% +/- 7.5% vs. 4.1% +/- 5.3%, p < 0.01). Importantly, the increase in Tregs in TILs occurred to the same extent in early and advanced disease. Furthermore, the frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells within tumors was significantly higher than that of normal gastric mucosa, and there was a significant correlation between the frequency of CCL17(+) or CCL22(+) cells and Foxp3(+) Tregs in TILs. In addition, the in vitro migration assay indicated that Tregs were significantly induced to migrate by CCL17 or CCL22. In conclusion, CCL17 and CCL22 within the tumor are related to the increased population of Foxp3(+) Tregs, with such an observation occurring in early gastric cancer.
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PMID:CCL17 and CCL22 chemokines within tumor microenvironment are related to accumulation of Foxp3+ regulatory T cells in gastric cancer. 1822 87

Increased populations of regulatory T cells (Tregs) impair anti-tumor immunity. Recently, the transcription factor Foxp3 has been reported to play a key role in CD4(+)CD25(+) regulatory T cell function and represents a specific marker for these cells. However, Foxp3 is a nuclear protein and is of limited value in the isolation of Tregs, which is a major reason that many functionally relevant aspects of Treg cells are still unknown. Here, we have characterized CD4(+)CD25(+)CD127(low/)- as the surface marker of regulatory T cells in gastric cancer. 88.1-96.1%of CD25(+)CD127(low/-) T cells expressed Foxp3, the frequency of CD4(+)CD25(+)CD127(low/-) regulatory T cells in the peripheral blood of gastric cancer patients was significantly higher than that in healthy controls. Increased CD4(+)CD25(+)CD127(low/-) regulatory T cells were also present in the tumor microenvironment, such as those found in the ascites fluid, tumor tissue or adjacent lymph nodes. Particularly those Treg cells associated with the TNM stage. In addition, we found that CD4(+)CD25(+)CD127(low/-) Tregs suppressed effector T cell proliferation and also correlated to advanced stage of gastric cancer. Thus, CD4(+)CD25(+)CD127(low/-) can be used as a selective biomarker to enrich human Treg cells and also to perform functional in vitro assays in gastric cancer.
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PMID:CD4(+)CD25(+)CD127(low/-) regulatory T cells express Foxp3 and suppress effector T cell proliferation and contribute to gastric cancers progression. 1915 62

MT110 is an EpCAM/CD3-bispecific antibody construct in clinical development for the treatment of patients with adenocarcinoma expressing EpCAM (CD326). Like other members of this antibody class, MT110 can engage resting, polyclonal CD8(+) and CD4(+) T cells for highly potent redirected lysis of target cells. Here we further explored the mechanism of this action. Complete lysis of EpCAM(+) Kato III gastric cancer cells by previously unstimulated T cells was achieved within 48 h. During this period, a high percentage of CD4(+) and CD8(+) T cells became activated and increased expression of granzyme B. This apparently boosted the capacity for serial target cell lysis as studied at very low effector-to-target ratios. Elimination of cancer cells by MT110-redirected T cells involved membrane damage as was evident from nuclear uptake of propidium iodide and release of the cytosolic enzyme adenylate kinase. Redirected T cells also potently triggered programmed cell death in cancer cells as was evident by membrane blebbing, activation of procaspases 3 and 7, fragmentation of nuclear DNA and cleavage of the caspase substrate poly (ADP ribose) polymerase. Chelation of extracellular calcium fully protected cancer cells from lysis by MT110-redirected T cells, while the pan-caspase inhibitor Z-VAD-FMK blocked activation of procaspases, cleavage of poly (ADP ribose) polymerase and fragmentation of nuclear DNA in cancer cells, but could not prevent nuclear uptake of propidium iodide. Soluble factors did not significantly contribute to cancer cell death. Our study shows that MT110 can efficiently gear up the potential of CD8(+) and CD4(+) T cells for serial lysis, and mediate kill of cancer cells predominantly through poreforming and pro-apoptotic components of cytotoxic T cell granules.
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PMID:Mode of cytotoxic action of T cell-engaging BiTE antibody MT110. 1915 37

Chronic infection with the bacterial pathogen Helicobacter pylori is a risk factor for the development of gastric cancer, yet remains asymptomatic in the majority of individuals. We report here that the C57BL/6 mouse model of experimental infection with the closely related Helicobacter felis recapitulates this wide range in host susceptibility. Although the majority of infected animals develop premalignant lesions such as gastric atrophy, compensatory epithelial hyperplasia, and intestinal metaplasia, a subset of mice is completely protected from preneoplasia. Protection is associated with a failure to mount an IFN-gamma response to the infection and with a concomitant high Helicobacter burden. Using a vaccine model as well as primary infection and adoptive transfer models, we demonstrate that IFN-gamma, secreted predominantly by CD4(+)CD25(-) effector T(H) cells, is essential for Helicobacter clearance, but at the same time mediates the formation of preneoplastic lesions. We further provide evidence that IFN-gamma triggers a common transcriptional program in murine gastric epithelial cells in vitro and in vivo and induces their preferential transformation to the hyperplastic phenotype. In summary, our data suggest a dual role for IFN-gamma in Helicobacter pathogenesis that could be the basis for the differential susceptibility to H. pylori-induced gastric pathology in the human population.
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PMID:The CD4+ T cell-mediated IFN-gamma response to Helicobacter infection is essential for clearance and determines gastric cancer risk. 1945 6

Helicobacter infection is the primary risk factor for gastric cancer, with the cytokine environment within the gastric mucosa the strongest predictor of disease risk. Elevated TNF-alpha, IL-1beta, and low IL-10 are associated with the highest risk. In this study, we used C57BL/6 mice to identify T-bet as a central regulator of the cytokine environment during Helicobacter felis infection. We infected male and female C57BL/6 and C57BL/6-T-bet knockout (KO) litter mates with H. felis and examined the bacterial colonization, immune response, and mucosal damage at varying time points. T-bet KO mice maintained infection for 15 mo at similar levels to wild-type mice. Infection and immune response did not differ between male and female mice. Despite sustained infection, T-bet KO mice respond with a blunted Th1 response associated with preservation of parietal and chief cells and protection from the development of gastric cancer. Unexpectedly, T-bet KO mice develop a gastric environment that would not be expected based on the phenotype of T-bet KO CD4 cells alone. T-bet KO mice respond to H. felis infection with a markedly blunted IL-1beta and TNF-alpha and elevated IL-10 levels. Activity of this one master regulator modulates the expression of the key gastric mucosal cytokines associated with gastric cancer and may be a target for therapy to restore immune balance clinically in patients at risk for gastric cancer.
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PMID:T-bet knockout prevents Helicobacter felis-induced gastric cancer. 1953 25

Helicobacter pylori (H. pylori) colonization induces vigorous innate and specific immune responses; however, the infection is not removed, a state of chronic active gastritis persists for life if untreated. Recent studies have shown that CD4(+) CD25(+) Foxp3-positive regulatory T cells (Tregs) suppress the immune response to H. pylori. Persistent H. pylori-associated gastritis is closely associated with gastric carcinogenesis. We investigated the number of Tregs in the context of H. pylori colonization in chronic gastritis, examined the relationship between it and histopathological findings and compared it with that of gastric dysplasia and adenocarcinoma. This study was based on the analysis of gastric biopsy specimens from 126 cases of H. pylori-associated gastritis, 16 cases of H. pylori-negative gastritis, 17 cases of gastric dysplasia, and 25 cases of gastric adenocarcinoma. The number of Tregs was elevated in H. pylori-associated gastritis, where it was positively correlated with the grade of chronic inflammation and the number of lymphoid follicles. It was significantly elevated in adenocarcinomas compared to chronic gastritis and gastric dysplasia. In summary, the number of Tregs is increased in H. pylori-associated gastritis and gastric cancer.
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PMID:The number of Foxp3-positive regulatory T cells is increased in Helicobacter pylori gastritis and gastric cancer. 1981 43


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